private var ttsErrorStatus: Int = 0 private var tts: TextToSpeech? = null

init { tts = TextToSpeech(context) { status -> ttsErrorStatus = if (status == TextToSpeech.SUCCESS) { TextToSpeech.SUCCESS } else { TextToSpeech.ERROR } }

val tts = tts

if (ttsErrorStatus == TextToSpeech.SUCCESS && tts != null) { // 默认设定语言为中文，原生的 android 貌似不支持中文。 ttsErrorStatus = when { tts.availableLanguages == null -> TextToSpeech.LANG_NOT_SUPPORTED tts.availableLanguages.contains(Locale.CHINESE) -> tts.setLanguage(Locale.CHINESE) tts.availableLanguages.contains(Locale.SIMPLIFIED_CHINESE) -> tts.setLanguage(Locale.SIMPLIFIED_CHINESE) tts.availableLanguages.contains(Locale.TRADITIONAL_CHINESE) -> tts.setLanguage(Locale.TRADITIONAL_CHINESE) else -> TextToSpeech.LANG_NOT_SUPPORTED } } }

/** * 设置音调，值越大声音越尖（女生），值越小则变成男声，默认值为 1.0 */ fun setPitch(pitch: Float) { val tts = tts ?: return tts.setPitch(pitch) }

/** * 设置语速，默认值为 1 */ fun setSpeechRate(rate: Float) { val tts = tts ?: return tts.setSpeechRate(rate) }

/** * 读文本 * @param content 文本内容 * @param utteranceProgressListener 阅读进度监听 */ fun speak( content: String, utteranceProgressListener: GetLastSegUtteranceProgressListener ) { val tts = tts ?: return tts.setOnUtteranceProgressListener(utteranceProgressListener)

when (ttsErrorStatus) { TextToSpeech.LANG_MISSING_DATA -> showToast(R.string.voice_missing_data) TextToSpeech.LANG_NOT_SUPPORTED -> showToast(R.string.voice_lang_not_supported) ANDROID_VERSION_NOT_SUPPORT -> showToast(R.string.voice_android_version_not_supported) else -> { if (tts.isSpeaking) { tts.stop() } else { val textSeg = genSegment(content, 10) utteranceProgressListener.setLastSegId(SEG_PREFIX + (textSeg.size - 1)) for (i in textSeg.indices) { // QUEUE_ADD：播放完之前的语音任务后才播报本次内容，QUEUE_FLUSH：丢弃之前的播报任务，立即播报本次内容 tts.speak(textSeg[i], TextToSpeech.QUEUE_ADD, null, SEG_PREFIX + i) } } } } }

/** * 将源文本分段 * * @param segmentLength 每一段的长度，最大设置 3999，大于 3999 将阅读出错 * @param originStr 源文本 * @return 分成的文本段 */ private fun genSegment(originStr: String, segmentLength: Int = 3999): Array { val originLength = originStr.length val arraySize = originLength / segmentLength + 1 val result = arrayOfNulls(arraySize) for (i in 0 until arraySize) { result[i] = originStr.substring(i * segmentLength, min((i + 1) * segmentLength, originLength)) } return result }

/** * 取得文本内容大约分钟长度 */ fun getSpeechLength(content: String): Int { val totalSecond = (content.length / 3.7).toInt() return totalSecond / 60 }

/** * 扩展 onDone 方法的进度监听 */ @SuppressLint("NewApi") abstract class GetLastSegUtteranceProgressListener : UtteranceProgressListener() {

private var lastSegId = ""

/** * 设置最后一段的 id */ fun setLastSegId(lastSegId: String) { this.lastSegId = lastSegId }

override fun onDone(utteranceId: String?) { onDone(utteranceId, lastSegId == utteranceId) }

/** * @param isLastSeg 是否是最后一段 */ abstract fun onDone(utteranceId: String?, isLastSeg: Boolean) }

companion object { private const val SEG_PREFIX = "seg" // 段落前缀 private const val ANDROID_VERSION_NOT_SUPPORT = -3 // 版本不支持 }}